[darren.naish@port.ac.uk: 52nd SVPCA meeting]

[Mike Taylor <mike@indexdata.com>]

Dear DMLers,

I'm forwarding this summary of SVPCA 2004 on behalf of ex-HP Darren
Naish.  I notice, skimming through this report (I've not read it
properly myself yet) that Darren gives an extremely sketchy report of
his own talk: "Darren Naish discussed _Yaverlandia_."  For those who'd
like to know more, you can read the abstract of his talk on the SVPCA
web-site at
        http://www.svpca.org/2004/abstracts/svpca-papers_a.htm#abst11
I leave it to him whether he wants to reveal the punchline in this
forum, or wait for it to be published.

One other note: my memory of Kristian Remes's talk differs from
Darren's in that I believe he recovered "Barosaurus" africanus as
closer to _Barosaurus_ than to other genera (but still a distinct
genus, for which he uses the name _Torneria_).

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From: "Darren Naish" <darren.naish@port.ac.uk>
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Date: Thu, 16 Sep 2004 12:19:04 +0100
Subject: 52nd SVPCA meeting
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Hey Mike - will reply to your emails later today. Please fwd 
this to the DML....

- ---------------------------------


The 52nd SVPCA was held at the University of Leicester 
from the 8th to the 10th of September 2004 (the field trip was 
on the 11th but I didnÂt go in an effort to keep costs down). 
The meeting ran really smoothly and many people have said 
how much they enjoyed it, though at least some speakers 
would have done well to do their homework on the AV 
facilities _before_ standing up and doing their talk. The 
meeting was also really well attended, with a higher turn-
out than some recent ones, and I also felt that the timetable 
was well balanced, with a good and fair representation of 
fish, Palaeozoic tetrapods, Mesozoic reptiles and mammals. 
Mammal talks were on marsupial functional morphology 
and ontogeny, lipotyphlan relationships, basal artiodactyls, 
Pleistocene hyaenas, and both Eocene and extant primates. 
Apologies to the workers involved and those interested, but 
(in keeping with my tradition of sticking to both 
palaeoherpetology and Mesozoic-oriented things) I have 
resisted the temptation to write reviews of those 
presentations too. I have also not reported on the posters: 
these included new details on _Hylaeosaurus_ (Gray and 
Chapman), humeral morphology of _Saturnalia_ (Gabriel 
and Langer), details of confuciusornithid morphology 
(Hughes), _Tyrannosaurus_ biomechanics (Hutchinson et 
al.), rhynchocephalian skull evolution (Jones), 
_Peloneustes_ (Ketchum), Miocene leatherback turtles 
(Lindow), a hyperossified Madagascan Cretaceous 
megafrog (Smith et al.), and others.

The group photo (or, as one speaker termed it, the Âstaring 
into the sun for five minutesÂ) was taken on the Thursday, 
and as some of you will know this is the day that _Nature_ 
published the parental care in psittacosaurs paper. This 
explains why IÂm holding up a page from a newspaper in 
the photo. Perhaps the highlight of the meeting was seeing 
Darwin himself depicted as Neo (with shades and long 
leather coat) in the title slide of Stig WalshÂs ÂDarwin 
versus The Matrix: does artificial intelligence have a place 
in vertebrate palaeontologyÂ?

The abstracts of the meeting have been published asÂ

Evans, M. & Forrest, R. 2004. _52nd Symposium of 
Vertebrate Palaeontology and Comparative Anatomy, 8th-
11th September 2004 and 13th Symposium of 
Palaeontological Preparation and Conservation, 7th 
September 2004, Abstracts_. University of Leicester.

My congratulations to the organisers (Mark Evans, Richard 
Forrest and Mark Purnell) on arranging such a fun and well 
organised meeting.

- -- Stem-group tetrapods

Jamie Robinson showed some fantastic animated 3D 
computer reconstructions of the basal temnospondyl 
_Dendrerpeton_. The specimen (BMNH R436) has both 
stapes preserved, with the left lodged inside the cranial 
cavity and thus invisible to human eyes. It seems that 
_Dendrerpeton_ had an impedence-matching middle ear 
homologous with that of anurans.

Jennifer Clack spoke about a new, fifth tetrapod taxon from 
Devonian East Greenland, collected in 1947 from Celsius 
Bjerg (the new taxon has a name, and this was used in the 
presentation). It includes good skull material, showing that 
it had a smoother skull texture than _Acanthostega_ and 
other taxa, and it also differs from other named taxa in 
lateral line morphology and dentition. 

Per Ahlberg reviewed our current understanding of the large 
stem-group Devonian tetrapod from Latvia, _Ventastega 
curonica_. _Ventastega_ is known from many many 
specimens representing most of the skeleton, this making it 
the most complete stem-group form after _Ichthyostega_ 
and _Acanthostega_. In details, _Ventastega_ more recalls 
_Acanthostega_ than other taxa, but appears to be even 
more basal than this genus. Like _Acanthostega_, 
_Ventastega_ has a bizarre internasal fontanelle (a median 
opening along the dorsal midline of the snout), the function 
of which remains unknown.

- -- Lepidosaurs

Susan Evans talked about the Lower Cretaceous lepidosaurs 
of Pietraroia, Italy. _Chometokadmon_, originally described 
as a lizard but later reinterpreted as a rhynchocephalian, is a 
lizard after all and clearly a scleroglossan, an anguimorph 
and perhaps a stem varanoid close to _Parviraptor_. 
Scattered osteoderms preserved in the region of the orbit 
and temporal region show that they were arranged in this 
area in a manner perhaps similar to that of extant 
_Lanthanotus_. Ardeosaurids (including a new species of 
_Eichstaettisaurus_ named after Steve Gould) and among 
the last Laurasian rhynchocephalians indicate that Pietraroia 
had a relictual lepidosaur fauna, probably because  like the 
rest of Europe at this time  it was a region of archipelagos 
and isolated islands.

Nick Arnold showed how different anatomical characters 
have different degrees of lability, and by considering this 
area more carefully we might be able to use these degrees of 
lability to better assess their value in phylogeny. For 
example, body size and the gracility and flexibility of toes 
in lizards are highly labile between closely-related taxa. At 
the other extreme, lizards which have fused their eyelids 
together end up lacking all of the structures associated with 
the maintenance of Ânormal eyes (e.g., they lack lacrimal 
glands and eyeball musculature), and they then seem totally 
unable to reverse this character. The implication from this 
for phylogenetic analysis is that characters which appear not 
to be labile, or in fact to be irreversible, should be weighted, 
though note that this is my interpretation and IÂm not sure if 
Nick actually stated this (sorry!).

Jason Head discussed an analysis of snake diversity in the 
Eocene sediments of the Hampshire Basin, an area 
preserving one of the best snake fossil records in the world. 
Application of PCA and statistical analyses to snake 
vertebrae (Jason was focusing in particular on erycines) 
show that previous taxonomic assignments are inaccurate 
and that the number of species within faunas are probably 
over-estimated.

- -- Plesiosaurs

Leslie Noe discussed the role of the plesiosaur neck, 
combining evidence from functional morphology, tooth 
wear, stomach contents, palaeoecology and 
palaeoenvironment. The morphological evidence from the 
plesiosaur neck indicates that dorsal and lateral movement 
of the neck was restricted, but that extensive ventral 
movement was possible. Long-necked plesiosaurs mostly 
seem to have lived in places where there was a diverse 
fauna of bottom-dwelling invertebrates, so the notion of 
plesiosaurs as grazers of the benthic fauna was advocated. 
Like grazing bovids, plesiosaurs may have spent a lot of 
time with the neck and head bent downward. Danger 
threatens (i.e., a pliosaur), and the plesiosaur relaxes the 
system, bringing the neck back into line with the rest of the 
vertebral column, and now it can escape at speed.

In ÂReinforced hoses and rhomaleosaursÂ, Richard Forrest 
pondered the internal structure of industrial and domestic 
hoses. Some hoses have circular reinforcement, with wire 
hoops perpendicular to the long axis. Richard couldnÂt find 
a tetrapod with this morphology and resorted to the neck of 
toy Imperial walkers, this being the second presentation I 
know of that has used Imperial ground-assault transport to 
illustrate a point (ask Matt Bonnan). In other hoses, 
reinforcement runs at 45 degrees to the long axis. In 
rhomaleosaurs, possible bracing structures in the cervical 
vertebrae (in the zygapophyses and rims of the 
synapophyses) are also aligned at 45 degrees, as apparently 
are the lines of reinforcement in the skull. This bracing 
system seems to be part of a functional complex in 
rhomaleosaurs, associated with their conservative cervical 
count (28 verts or thereabouts). Rhomaleosaur diversity 
seems to be higher than presently reflected in the literature, 
with various new, unnamed taxa sitting in various 
collections. Lower Jurassic plesiosaur diversity is probably 
far higher than currently recognised in fact (see also 
GrossmanÂs data, below).

Norton Hiller reviewed elasmosaurid diversity in the Late 
Cretaceous of New Zealand  besides _Mauisaurus haasti_ 
and _Tuarangisaurus keyesi_ there are two other, new taxa. 
One of these is represented by a good pectoral girdle. This 
preserves an unusual craniocaudally elongate sulcus on the 
medial surface of the coracoids and a massive prominent 
spike-like process on the ventral surface. The latter feature 
is not entirely novel as itÂs also seen in a new elasmosaurid 
being described by Pat Druckenmiller. Norton wasnÂt aware 
of any possible function for this spike but in discussions 
with Colin McHenry IÂve learnt that it is probably related to 
the presence of a sternum. Supposed records of 
_Tuarangisaurus_ and _Mauisaurus_ from Antarctica and 
southern South America are dubious and probably mostly 
not referable to these taxa.

Franziska Grossmann gave a talk on the good Lower 
Jurassic plesiosaur record from the German Posidonia shale 
and new reconstructions were presented on the hitherto 
neglected taxa _Plesiosaurus guilelmiimperatoris_ and _P. 
brachypterygius_, both are which are quite different in 
many details from _P. dolichodeirus_ (the type of the 
genus). IIRC, _P. guilelmiimperatoris_ had a particularly 
odd, box-like skull shape. _P. brachypterygius_ has a more 
conventional plesiosaur skull. Inclusion of these taxa within 
a novel phylogenetic analysis showed that, as expected, 
they are well aware from _P. dolichodeirus_.

- -- Pterosaurs

David Unwin combined various lines of evidence to paint a 
well integrated and supported view of pterosaur 
reproductive biology. ItÂs the first conference presentation 
IÂve ever seen that was illustrated with Jenny Halstead 
illustrations, but then you canÂt have everything (sorry, I am 
not a fan). Pterosaurs were clearly oviparous and new 
specimens confirming this are in press. The eggshell of the 
new embryo does not appear to be calcareous as argued but 
indicates instead that pterosaur eggshells were leathery. The 
recently described Chinese embryo plots with adult 
ornithocheiroids in terms of limb proportions, and all 
indications are that baby pterosaurs were precocial and able 
to fly soon after hatching. Preserved soft tissues show that 
hatchling pterosaurs had wing membranes as extensive of 
those of adults and pterosaur growth rates were slow 
compared to those of birds and bats.

- -- Mesozoic faunas etc.

Steve Sweetman spoke about his many new discoveries 
from the Isle of WightÂs Wessex Formation. There were 
pretty much no published Wessex Formation 
microvertebrates prior to SteveÂs work  now there are 
loads: multiple new taxa of lissamphibians 
(albanerpetontids, salamanders and frogs), lizards, and 
mammals (including MTBs, spalacotherioids, and basal 
zatherians). There are also various strange little dinosaur 
teeth, some of which are problematical (e.g., those that 
resemble basal ornithischian teeth), others of which are new 
records (e.g., troodontids).

Jean-Paul Billon-Bruyat reviewed the Kimmeridgian fauna 
of NW Switzerland, as revealed by body fossils and 
trackways. The environment represents a shallow carbonate 
platform, and chelonian and crocodyliform elements are 
present. A fragment of pterosaur has been discovered, but it 
is literally only a fragment. Numerous sauropod and 
theropod trackways are present which, in the case of the 
sauropods, raised the question as to what the animals were 
doing there. They actually appear to have been making a 
living in the area and not simply passing through (as has 
been argued for other marginal environments with 
herbivorous dinosaur taxa).

Mike Benton discussed Âecosystem remodelling across the 
P-Tr boundary as documented in the record of the South 
Urals basin. A fundamental change and simplification in 
guild structure occurred across the boundary  small 
piscivores and insectivores, mediun and large carnivores 
and large herbivores were all lost, and these guilds remained 
empty for 25 million years after the extinction event.

- -- Chelonians

Sarah EarlandÂs talk title ÂTurtle taphonomy and tuna fish 
sandwiches was explained as a clever ploy to attract 
attention to a talk whose content did not necessarily match 
that of the title. Basically: what happens to dead turtles that 
rot in water? Very little has been published on turtle 
taphonomy, so actualistic work is needed. Think crabs, 
maggots, bacterial films, dangling limbs 

- -- Crurotarsans

Rebecca Smith analysed various characters in the 
steneosaur skull to see if the various species reported from 
the Upper Lias of the Yorkshire coast were valid and could 
be distinguished, a study initiated by the rediscovery of a 
skull referred to _Steneosaurus brevior_. The measurements 
taken (e.g., orbit width) were compared to sets of 
measurements of the same features taken from a wide 
sample of extant crocodylian species to see how labile these 
features were. 

- -- Dinosaur biology, diversity etc.

Phil Manning addressed various aspects of 
palaeoichnology. Phil argued that underprints, ghost prints, 
transmitted prints or whatever you want to call them are far 
more common than has been hitherto recognised  in fact, a 
quick analysis of the published track record suggested that 
something like 80% of all published dinosaur tracks were 
not the actual surface tracks themselves, but underprints! 
Accordingly, the distortion of sediments must be an 
important factor in print anatomy. Indeed, the deeper the 
same print is transmitted through the sediment, the more 
different it becomes, such that the interdigital angles of a 
deep impression is >totally< different from a shallow 
impression of the same track. This all casts significant doubt 
on proposals that dinosaur groups with similar foot anatomy 
can be reliably distinguished from tracks, and it also 
indicates that track ichnospecies are massively oversplit.

Mike P. Taylor summarised his study of non-avian dinosaur 
diversity, looking at diversity within clades, geographic 
regions and year based on all valid genera recognised as of 
2001. Some ornithischian groups (pachycephalosaurs and 
stegosaurs) are taxonomically insignificant and theropods 
proved ridiculously abundant proportionally. The 
Kimmeridgian and Campanian were the most dinosaur-rich 
stages. The naming of taxa over history is interesting, with a 
plateau between the wars and a massive rise within the past 
19 years: more taxa have been named in this time than 
during the preceding 158 years.

John Hutchinson posed the fundamental question can we 
incorporate enough information into biomechanical 
modelling to ever get even close to real-organism 
modelling, or are we just **cked? (his words, not mine). 
Things need to move on a long way from the important 
studies of Alexander, and one of the take-home points was 
that we need far more people working on extant animals, 
many many aspects of which are still not understood or 
even not studied at all. The use of elephants and rhinos as 
analogues for dinosaur locomotion for example (as per 
Alexander, Bakker and others), is problematic as the 
biomechanics of these species are horribly understudied. 

Oliver Wings covered the results of his project on gastrolith 
distribution and function. Some lovely photos of dissected 
ostrich stomachs. While gastroliths have been reported 
widely among birds, their reported presence among birds of 
prey (falconiforms and strigiforms) appears due to ingestion 
of other animals which were instead the proper Âowners of 
the gastroliths. Many non-avian dinosaurs for which 
gastroliths have been reported (including all theropods 
except _Caudipteryx_ and _Sinornithomimus_ and all 
thyreophorans) have only ever been discovered with one, 
two or a few gastroliths. This suggests accidental ingestion, 
not deliberate employment. OliverÂs most controversial 
assertion was that sauropods could not have used gastroliths 
for digestion because they never preserve a mass of stones 
big enough to have made a digestive difference. Paul 
Upchurch thought that this was problematic because it 
assumed that sauropods had a digestive apparatus and 
metabolism just like that of birds.

- -- Sauropodomorphs

Tim Fedak gave a presentation on his work on the Nova 
Scotian sauropodomorphs of the McCoy Brook Formation. 
New specimens include adults, subadults and juveniles and 
details of the ilia and other elements show that these are not 
_Ammosaurus_ as previously thought, but a new taxon. Tim 
has been working on the histology of this taxon and also 
considered various aspects of ontogeny, growth rates and 
histological variability. There appears to be a new taxon of 
theropod in the McCoy Brook Formation.

Andreas Christian applied analysis of compressive forces to 
sauropod necks  those of you familiar with this research 
will known thatÂs been applied to _Brachiosaurus_, the 
conclusion from Christian et al. being that _Brachiosaurus_ 
had a vertical mast-like neck. Christian explained the 
technique, showed that it worked when applied to such 
living animals as giraffes and camels, and then applied it to 
other sauropods. The data from _Diplodocus_ indicates a 
horizontal neck but that from _Euhelopus_ indicates that it, 
too, had a mast-like vertical neck.

Kristian Remes presented a reanalysis of the type material 
of the Tendaguru sauropod _ÂBarosaurus africanus_. While 
this valid taxon does indeed seem to be a diplodocid 
diplodocoid, it is not closer to _Barosaurus lentus_ than to 
other taxa, and indeed is significantly different from it in 
many features. Kristian therefore argued that the older name 
_Tornieria africana_ should be resurrected for this taxon. 
Rebbachisaurid distribution indicates that diplodocoids 
were ancestrally Gondwanan (though _Histriasaurus_ was 
not mentioned): Paul Upchurch countered this by arguing 
that the groupÂs distribution was more likely ancestrally 
global, with their post-Callovian distribution being due to 
vicariance.

Also on diplodocoids, Daniela Schwarz covered her new 
work on reconstructing the cervical column pneumaticity of 
_Diplodocus_. Daniela showed many fantastic photos and 
complex reconstructions, covering both juveniles and adults 
and with an attempt to reconstruct the ontogenetic changes 
that occurred. The models of air sac distribution were 
extremely detailed and highly complex, and pneumaticity 
became more complex during ontogeny. As well as air sacs 
lateral to the centrum, dorsal to the neural arch and 
elsewhere, there is evidence for several sacs within the 
neural canal.

- -- Theropods

Steve Hutt presented data on a recently discovered 
spinosauroid dorsal vertebra from the Barremian Wessex 
Formation of the Isle of Wight. After eliminating 
_Neovenator_ and _Becklespinax_, Steve showed that the 
specimen was highly similar to the dorsal vertebrae of the 
_Baryonyx_ holotype, albeit it with a far taller neural spine. 
The spine is in fact comparable to that of _Suchomimus_. 
However, careful examination of the _B. walkeri_ spines 
show that they are not complete but in fact only one-third 
so, and the holotype probably originally had neural spines 
comparable to those of the new Isle of Wight specimen. 
Steve agreed with other authors that _Suchomimus_ is 
probably not a distinct genus but a species of _Baryonyx_.

In a second talk on spinosauroid material, Eric Buffetaut 
revealed new good theropod postcrania from the Lower 
Cretaceous Sao Khua Formation of Thailand. This material 
is associated with teeth referable to _Siamosaurus 
suteethorni_ and is thus probably also referable to this 
species, though this canÂt be established without question 
because the teeth could be there because of scavenging. The 
cervical and dorsal vertebrae of the new specimen are 
highly similar to those of _Baryonyx_ in many details, 
similar enough to establish the spinosaurid spinosauroid 
nature of the new specimen with confidence. The tall neural 
spines on the dorsal vertebrae were comparable with that of 
the _Baryonyx_ vertebra described by Hutt in the previous 
presentation. 

Darren Naish discussed _Yaverlandia_.

Gareth Dyke reported new bird material from the Upper 
Cretaceous Northumberland Formation of Hornby Island, 
British Columbia. Like the rest of NW North America, this 
area is part of an accreted microterrane and was not a part of 
the North American continent during the Cretaceous, thus 
its taxa may well be closer to animals from elsewhere 
(notably eastern Asia). The birds represented are known 
from isolated bones of apparently marine taxa and include a 
euenantiornithine and an ornithurine that may be an 
ichthyornithiform. The euenantiornithine was compared to 
_Halimornis_. 

David Waterhouse showed his new psittaciform phylogeny. 
With the exception of one problematic taxon, pseudasturids 
were stem-group psittaciforms (as argued recently by 
Gerald Mayr) and several psittacid groups proposed by 
other workers to be clades were also supported as 
monophyletic, including cockatiels and cockatoos, lorikeets, 
and South American taxa. _Coracopsis_ (vasa parrots) were 
close to the psittacid root, which again is interesting 
because other people have suggested this based on other 
bits of evidence. Several characters which exhibit 
interesting (and presumably phylogenetically significant) 
diversity remain to be coded across all taxa, and this will be 
the subject of future work. These characters include bill 
shape, feather pattern and the presence of feather patches 
that fluoresce under UV light.

- -- Synapsids

Arthur Cruickshank discussed the _Dicynodon_ species of 
the Upper Permian of Morayshire, Scotland. A natural 
mould of a virtually complete skull was examined by way 
of CT-scanning, MRI and other techniques and various 
details showed it could be referred to _D. traquairi_, and 
Arthur asserted that this species can be distinguished from 
_D. lacerticeps_. Some of these species have a notch in the 
dentary symphysis which suggests that they might have had 
a prehensile tongue, though IÂd be interested if thereÂs any 
evidence from the hyoids or elsewhere in agreement with 
this (dicynodont hyoids were pretty gracile so far as I 
know).

Tom Kemp advocated a fairly controversial point of view 
that many of us who work on morphology might not like 
hearing. Attempts to reconstruct the total phylogeny of 
placentals were never particularly convincing, nor did they 
produce well resolved trees, nor were any nodes supported 
by multiple characters. It is the many independent molecular 
studies that seem to have sorted things out. Kemp therefore 
argued that morphology alone can probably never get it 
right, and if we look at phylogenies for fossil taxa we see 
that some trees, and some nodes in trees, are incredibly 
weak, and maybe we should have next to no confidence in 
these phylogenies (non-mammalian therapsids were used as 
the case study). Robert Asher pointed out after this talk that 
maybe this point of view was somewhat negative: after all, 
morphological work had been able to recover at least some 
chunks of the clades recognised by molecular work (e.g., 
morphology-based Archonta constitutes a chunk of 
molecular Euarchontoglires and morphology-based 
Paenungulata constitutes a chunk of molecular Afrotheria).

Robert Presley showed quite convincingly that the groove 
on the medial surface of the Mesozoic mammal mandible 
should not be called Meckelian sulcus or anything like this 
and for various reasons we should return to calling this 
structure Âinternal mandibular grooveÂ.

Ian Corfe reviewed the taxonomy of _Oligokyphus_ and 
showed that various tooth-cusp characters used to 
distinguish putative species were erroneous and some 
named species, when examined using quantitative 
morphometrics, plotted together.  

- -- 
Darren Naish
School of Earth & Environmental Sciences
University of Portsmouth UK, PO1 3QL

http://web.port.ac.uk/departments/sees/staff/NaishD.htm
email: darren.naish@port.ac.uk
tel: 023 92846045
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